package algorithm.leetcode.problem_92;

public class answer_1 {
    public class ListNode {
        int val;
        ListNode next;

        ListNode() {
        }

        ListNode(int val) {
            this.val = val;
        }

        ListNode(int val, ListNode next) {
            this.val = val;
            this.next = next;
        }
    }

    class Solution {
        public ListNode reverseBetween(ListNode head, int left, int right) {
            ListNode dummy = new ListNode(-1);
            dummy.next = head;
            ListNode pre = dummy;
            for (int i = 0; i < left - 1; i++) {
                pre = pre.next;
            }
            ListNode cur = pre.next;
            ListNode next;
            for (int i = 0; i < right - left; i++) {
                next = cur.next;
                cur.next = next.next;
                next.next = pre.next;
                pre.next = next;
            }
            return dummy.next;
        }
    }
}
